Burbank, summer 1985. Young Howie and his friends have lost a baseball belonging to Howie's father. It's a unique baseball in that it has Babe Ruth's autograph. Kate and George determine, through mathematical and physical laws, that the ball entered a house. Apparently Mrs. McGregor left her door open when she left for the store. So the valuable baseball is in Mrs. McGregor's house. When Kate and George call her the next day, they learn her house has been stolen.

Los Angeles, 1986. A grocery store is robbed of 20 pounds of bananas, the first of several heists apparently done by a gorilla. When the L.A. Zoo reports a gorilla missing, Kate and George are convinced he is the guilty party. Only the gorilla's friend, a teenage girl named Jane, stands to the gorilla's defense.

Santa Monica, 1986. After the Mathnetters help estimate the crowd at a parade honoring rock star and Burbank native son Steve Stringbean, they get word Stringbean has been kidnapped. His buddy Rimshot helps Kate and George immensely on the pursuit of the kidnappers. One strange lead is a badly-written march called 75 Trombones.

Los Angeles, May 1986. George Frankly comes back from a week in the Great North Woods. He has just heard of a robbery at the Next to the Last National Bank three days before. When he and Kate look at the bank's videotape recording of the robbery, they see the impossible: George is doing the heist. Evidence piles up against George as his preliminary hearing looms. George knows he is innocent, as does Kate. But can they prove it?

Glendale, 1986. Three truck drivers call within six hours to report that their dump trucks full of dirt have been stolen. Initially, this ""Case of the Missing Dirt"" turns up a long-lost tale about Merle Fish, the man who pulled off the Finks Armored Truck Robbery in 1965. Rumor had it he had an accomplice who took the money and left the country. This is all explained in a book written by the fishy Norman Mailbag.

L.A. County, April 1985. Two crimes start separately, but merge a few days later. Multi-talented Hans Ballpeen is kidnapped for one of his special skills. Before they can bear down on this case, Kate and George must help with the delivery of an oak hamburger to the mansion of tycoon Orson Kane. Within a day, Kane reports that one of his prized possessions, the Despair Diamond, has been stolen.

Los Angeles, September 1988. For two months, the number of stolen cars in the area has skyrocketed. An estimated 20,000 cars have gone missing–permanently. Amidst all the data, Kate and George do find certain ""preferences"" in what kind of cars are stolen. But can they figure out what has happened to the cars?

Los Angeles, 1988. A shocking development in the rapidly-deteriorating TV scene: The Mike Pliers Show has been canceled. The leader of the Mike Pliers Fan Club wants to know the truth behind its axing. With the Mathnetters at her side, she learns that it all comes down to ratings and Nielsen boxes. But these numbers don't add up to what they say.

Los Angeles, 1988. Kate is out with an injured foot, leaving George Frankly to investigate a strange set of pranks. One by one, a different brand of bank falls prey to a prank, and the hoodlum responsible leaves a poetic note on a bank slip. But there's more to the caper than that, as Kate telephones in to say she has looked through the rear terrace. She has seen someone working on plastique bombs.

Los Angeles, fall 1988. For some time, a ""prognosticator"" named Sybil Divine has been exposing her apparent ability to predict earthquakes. She intends to extort money from L.A. Mayor Quail [sic] with her big scam. Everyone in town is convinced she can predict the big quake that will rock Southern California within the next half-century. Assistant Chief Rosa Morales knows better, as do Kate and George. They must prove it.

New York City, November 1988. Kate and George have just moved in to the Mathnet division at NYPD, with a new chief and a new ally, cabdriver Benny Pill. As they are fresh off ""The Case of the Ersatz Earthquake,"" Kate and George are well-prepared to hear about another prognosticator. This guy worked long hours to swindle five prominent city lawyers out of a few thousand bucks by predicting the results of a horse race.

Rivervale, New Jersey, 1991. In the minor leagues, a journeyman baseball player attempts to attract every major club's attention. Roy (Lefty) Cobb is hitting a ball at 143 miles per hour for a wicked batting average. A sneaky agent is following him everywhere, or, more correctly, Cobb is following him. Pat Tuesday, George's new partner, gets to meet Cobb on the field, thanks to his good friend, who plays a game of number sequences with him. But those aren't number sequences. They are codes.

Armed with a search warrant, Captain Greco and George search Pat's apartment, where they believe a particular (and very expensive) bracelet has been stolen and hidden by her.